Mystery Sound and Broken Chain

[George Schick]

Ever since I've owned my Ram I've had a unique, loud clunking or crunching sound coming from the drive train, especially when I started from a standing stop or occasionally when hammering up an incline.  I used to associate it with the "ghost shifting" phenomenon as posters here referred to certain chain and cassette indexed shift combinations.  But this loud "clunking" sound never resulted in an unwanted change in gears; it just sounded like something that shouldn't be happening.

Well, this has gone on intermittently since about 2004.  Yesterday, however, the chain broke.  Broke completely in half, both sides after starting from a standing stop again.  Fortunately, I was carrying a spare SRAM Powerlink and the event took place while crossing an intersection near a strip mall that had a bike shop.  I borrowed their chain tool to drive out the pins of the broken link and installed the Powerlink and took it easy on the way home, worried that it might happen again.

My question is:  What the heck gives??  The chain is a SRAM 971 which is designated as the proper chain by the manufacturer for 9-speed cassettes.  The cassette is a 9-speed Shimano hyperglide, and the crank/chainrings are Velo Orange Cru.

[Bill Lindsay]

George indicates that he's had a loud clunking or crunching sound coming from his bike for 18 years under hard pedaling.  He asks "what the heck gives?"

Have you tried to address it in any way?  What have you tried?

Generally these "my bike makes sounds I don't like under hard pedaling" involve changing one thing at a time and using the changes in the sound to narrow down the source.  If you've been riding the same SRAM 971 chain for 18 years, and you actually ride the bike a decent amount, then your entire drivetrain is likely toast.  Is that what's going on?  Or, do you replace your chain frequently, and the noise never changes?  If that's the case, then you've likely ruled out the chain itself as the source.  

Have you tried riding your bike with different pedals?  If the noise is the same with different pedals, then it's probably not the pedals.  

Have you tried riding your bike with a different rear wheel?  If the noise is the same with a different rear wheel, then the rear wheel is probably not the source.

Is the noise the same regardless of which front chainring you are in?  If so, then one chainring is probably not the source.  

Have you pulled the crank arms of and checked the BB bearings?

Sometimes, a headset problem can feel like drive train noise.

If you don't want to dive into iterative and time-consuming diagnostics, have a mechanic you trust look into it,

Bill Lindsay

El Cerrito, CA

[George Schick]

Bill - thanks for the quick response.  Bill asks...

(have you been) riding the same SRAM 971 chain for 18 years, and you actually ride the bike a decent amount, (if so) your entire drivetrain is likely toast.  Is that what's going on?  Or, do you replace your chain frequently, and the noise never changes?

I can't recall whether I've had that same chain in use on that bike for 18 years.  I regularly clean and lube it and check the chain wear with a Park chain gauge.

Have you tried riding your bike with different pedals?

Yes, and it has still occurred over the years.

Have you tried riding your bike with a different rear wheel?

No, this bike has always had that same rear wheel, a Shimano Dura Ace hub, a Velocity OC rim, and Wheelsmith spokes.  I've removed, cleaned, and re-lubed the rear axle several times over the years and I've never noticed any uneven wear on the bearing races.

Is the noise the same regardless of which front chainring you are in?

The crank has a Velo Orange Cru with 48/34 chainrings.  It originally had a TA Syrius crankset with similar chainring sizes and it did the same thing then.  Because of the relatively flat terrain in NE Illinois I ride in the larger 48 tooth chainring 95% of the time.  The small chainring is only used for longer steep climbs such as ones up from river bottoms to ridges at the top.

Have you pulled the crank arms of and checked the BB bearings?

The BB on this bike now is a Phil Wood and it has never given any indication of a problem.  I have pulled the crank arms of, as you say, on occasion when I noticed a different kind of clunking noise (though quieter) and found that the fixing rings were loose.  I took care of that problem with LocTite and it has not occurred since.  The original BB was an Axxis and the clunking noise was present even then.

Sometimes, a headset problem can feel like drive train noise.

The headset on this bike had indeed indexed a number of years ago, but I swapped it for an IRC roller drive and it's been fine ever since.

If you don't want to dive into iterative and time-consuming diagnostics, have a mechanic you trust look into it,

Don't know of one in the area.  Mostly just guess-work types who try to swap this out for that, sometimes with success and other times not..

Nevertheless, thanks for your diagnostic suggestions, Bill.  Are you in SE Michigan these days or back in NoCal?

[Bill Lindsay]

George

I'm in California

Just to rule it out, grab a middle-ish cog in the cogset and give it a wiggle.  Does it wiggle relative to the other cogs or are they all really secure relative to one another?  If it wiggles, then maybe the lockring is loose.  If the lockring is tight but the cogs wiggle then maybe the stack up of the cassette is too short for the length of the freehub and you need to add a spacer.

Bill Lindsay

El Cerrito, CA

[Joe Bernard]

It could be anything but what I think we know now is the chain is busted and chain and cassette are both probably pretty old. Based on my supposition - pulled out of thin air - that your chain never mated well with that cassette I would replace both now and see what happens. 

Joe Bernard

On Monday, May 30, 2022 at 12:23:13 PM UTC-7 George Schick wrote:

[George Schick]

Bill - you raise a good point.  None of the cogs wiggle, but I can't remember if they're keyed as they slide onto the free hub splines.  Looking at the way the teeth on the cogs are arranged as the free hub turns makes me wonder if they get into a certain position and "think" they need to shift, but then can't, making a loud unforgiving sound.  IOW, a link may be getting caught crossways between shifting and not shifting, causing not only the sound, but leading ultimately to the broken side plates.  Not sure what to do about this.  Placing the bike on a work stand with new chain installed and moving the RD through all of the cassette gears, rotating the pedals both forward and backward (freewheeling) yields no kind of sound whatsoever.

[George Schick]

Joe - I thought about that and have since replaced the chain, but in all likely hood the cassette should still be OK.  It's not the original with the bike; I replaced the one with which the bike shipped with another (same manf.) that has slightly different gearing.  The previous cassette had the same problems.

[Joe Bernard]

Huh, I'm stumped. It crunches under hard pedaling and this time the chain snapped, which sounds like the chain wanted to keep going and something back there didn't want to budge. How's the clearance between small cog and chainstay? This is my last shot at a wild guess..maybe under heavy power the cassette is contacting the frame at the dropout. 

[George Schick]

Joe - the chain is rarely, if at all, on the smallest cog next to the chain stay.  It is normally in either cog 4 or 5, counting from the largest cog outward.  I can remember when a company by the name of Sedis (Sedisport?) first introduced a narrower chain back in the late 70's in order to squeeze more gears onto a freewheel with normal 120-126mm rear dropout spacing.  In my opinion, it's been downhill ever since with manufacturers trying to outdo one another with wider and wider dropout spacing and 9+ cogs.  OTOH, I have an old '71/'72 Fuji Finest on which I'm running a 5-speed freewheel on a 120mm PW hub, friction shifted, and everything works just fine all the time.

[Garth]

George, Have you ever cleaned/relubed the cassette/freewheel(whichever the DA is) body itself ?  I know you've mentioned the bearings, but not the cog host body. 

I'm with you about the "more gears and wider dropouts" nonsense . I have a good selection of Sachs and Suntour Ultra 6 and 7 speed freewheels of which I'm seriously considering using for my upcoming Franklin custom. I'm really not fond of anything to do with cassettes.The cassette so-called "solution" was but a self-fullfilling sales pitch/excuse for "more more more". Hah hah.  I have 2 sets of Specialized 126mm hubs of which I have converted in the past to 135mm using a solid axle. I could have the frame spec'd to whatever I want though, and buying more vintage NOS hubs of various widths is not a problem. 

[Bill Schairer]

It wouldn't hurt to check the alignment of the dropouts and derailleur hanger.

Bill S 

San Diego

[George Schick]

Garth - I have not done anything to the freehub body.  That's a good recommendation and I'll have to address it.

Bill S - good point.  This frame is one of Grant's "tweeners'; somewhere between 130 and 135mm spacing so it will accommodate either road or MTB hubs.  I don't think that will cause any issues, though, but it might be worthwhile taking it to an LBS and have them check to make sure the dropouts are parallel.

[Ian A]

Maybe take a close look at the right-side dropout to make sure it does not have a crack in it. Normally, if a dropout cracks, failure is soon behind, so it's unlikely to be the problem in your case, but it is something to rule out.  My friend had his go on his old Raleigh, on the drive side, but I don't recall it making worrying noises before it went. 

IanA Alberta Canada

[Bill Lindsay]

George

Getting back to the problem you are trying to solve:  Does your instinct tell you that there's something broken or incorrect, and that faulty condition is warning you with sound?  -OR- is this sound more of something you just notice.  You feel an expensive bike should be silent and sometimes you hear something, and you'd prefer to hear nothing from your expensive bike?  

Do you have an instinct on this?  There are definitely a lot of cyclists of a certain age who recall having ridden a silent bicycle back in the day, who now dislike anything newer or more modern on the grounds that it's no longer silent.  Back in the eearly to mid 1990s I was largely a Campy-guy, purely on the grounds that a Campy drivetrain in that era (8sp ergo) was silent while pedaling.  Shimano definitely shifted better but Shimano was not as silent "in gear" as Campy was.  The pedaling feedback into my feet was one of fluidity.  With Shimano, I felt that the sound and the feel would constantly remind me I was operating a chain-drive drive train.  Campy allowed me to forget that.  I couldn't feel it, and I associated that with "quality".  

Could that be part of what's going on here?

Bill Lindsay

El Cerrito, CA

[Joe Bernard]

Bill (this is Joe, not George), I've had that noise madness with SRAM cassettes. Chains sound all rattly and crunchy on them and I'm just not into it! 

Joe Bernard

[George Schick]

Bill - oh, there has definitely been something going on all these years that's just not right vs. a perceived but unrealized perfection associated with a high-end bike.  The reason why I'm assuming that the crunching/grinding had to do with the chain breakage is because it was starting to make the noise when the chain snapped.  If I could just get it to happen when I have it on the work stand I could then see what's going on between the chain and the rear cogs or the chain ring.  'Course, part (or maybe even most) of the reason why it won't happen on the work stand is because nothing on the drive train is under a load.

[Joe Bernard]

Is the chain jamming between the big ring and a too-low front derailleur?

[George Schick]

Joe - not that I can tell.  First of all, I'd likely see it if that happened.  Secondly, it would occur much more frequently than this sporadic, isolated business. 

[Bill Lindsay]

OK, well if there has been something wrong with your bike's set-up and you've used it for 18 years with that wrong set-up, then it's probably a pretty good bet that whatever is set up wrong will need to be replaced by now.  If you think that the wonky part contributed to a chain breakage then at minimum you should replace your cassette.  If you believe you've eliminated the BB, crankset, pedals and headset, then that leaves the rear wheel.  The last maintenance checklist item that has not been addressed in this thread is the bolt that holds the freehub body onto the rear hub.  You'd snug that up with a 10mm allen key next time your rear axle is out.  I imagine that could make a noise under hard pedaling if it was loose.  

I don't recall if you've said so, but are you friction shifting or index shifting?  Barcons, or downtube, or brifter?  

I'd still recommend riding the bike with a different rear wheel.  130mm OLD rear wheels with 9-speed cassettes are totally common.  

[George Schick]

Thanks Bill - I believe that you and Garth both point to the free hub body correctly.  I'll take a look at that, though if the pawl's in the free hub body are sticking (apparently common on some manf's of these) then one would expect the pawls not to be engaging the ratchet teeth properly, therefore a slipping free hub, not a false engaging of a gear and a subsequent loud crunching sound.  I'll check the tightness of the bolt that holds the free hub body onto the hub to see if that might be loose.  BTW, the cassette on this hub is the second one since purchasing the bike.  I did not like the gear combination on the one that came with the bike.  But, of course, the free hub body onto which it was installed is the original.

Otherwise, thanks to all y'all who chimed in with recommendations about what might be wrong.  That's what I like about this blog site - everyone chips in to help out everyone else who posts with a problem.

[George Schick]

Resurrecting this thread briefly to announce that I found the problem (at least I'm pretty sure anyway).  After replacing  the broken chain with a new one not only did the same intermittent problem still occur, but I also noticed that the chain was having problems when  being shifted onto the next to the smallest cog while it was on the inner chain ring.  That should never be.  So, after doing some remedial online research on Sheldon's website I came across a link for determining proper chain lengths.  Followed the instructions and discovered that my chain was too short.  I had removed enough links on the new one to match the broken one, which was why the problem still existed.  Added a link and everything seems to be running smoothly.  I feel pretty embarrassed.  After all these years of working on bikes I should have known to check that.

[Garth]

Very good George !